In the traditional shellfish breeding methods requiring shallow seabeds in quiet waters, matter is produced, which, in high concentrations, perturbs and offsets the balance of the surrounding ecosystem. This environmental pollution has a negative effect on the ecological balance by causing a decrease in the plankton flow and a drop of the feeding rate of the shellfish, with a consequent reduction of the desired production of cultures.
Other self-supported installations are also constructed for breeding shellfish, such as that disclosed in the document ES 1043285U by Carceller, which describes a live well improved for growing mussels in open sea, comprising a rope or longline from which the breeding ropes are hanging and which is maintained in a horizontal position once extended and grounded by means of weights anchored on the sea floor, while subjected to the uplift force exerted by a plurality of buoys or floats to which it is attached in combination with a plurality of surface floats, the live well is provided with an improved support and beaconing facility.
These already existing installations, in particular those with self-supporting flotation buoys, have proven their open sea capabilities but have the drawback that the impact of the waves and the weight of the load during vertical movement can not only cause the detachment of the animals due to rupture of the supporting byssus, but can also result in exhausting or stressful situations for some breeding species.
Although these open sea installations allow mooring the ship to the longline to facilitate collection of the harvest, no description is available in respect to the handling of the longline which we suppose is raised by crane, normally a difficult procedure.
A further negative effect on the crop is caused by the necessary maintenance of the line at a height normally equidistant to the seabed, this being established depending on both the length of the chains used to connect the ends of the longline to the dead weights holding the chains to the sea floor as well as the upwards lift from the floaters.